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<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <script>
    // 以下声明变量的方式哪些是对的，哪些是错的
    //  let if = 10
    // let num1$_ = 11
    // let nav-bar = 11
    // let 1num = 10
    // let $_666 = 666;
    // let _11 = 120;
    // let age = 10;
    // let Age = 20;
    console.log(age,Age)
  </script>
</body>

</html>